Normal Ekg during stress test Abnormal Echo?

I went to see my doctor because my heartrate at rest has been over 100, and leisurely activity has often taken me over 120-130.  I did not have a problem with this until 2 months ago (thats when the high heartrate started) and was no  longer allowed to donate plasma.  I am 25 year old female, slightly overweight, very active though.
The doctor sent me to a cardiologist after confirming through a holter monitor that my heartrate is high for the entirity of the day, even during sleep.  THe cardiologist recomended a stress echo.  The nurse monitoring the ekg kept saying throughout the test that my "EKG is sooo normal, exactly what we expect" then during the echo, he kept talking about how my ekg is soo normal, but the echo tech said nothing.It took me 4 days to get my echo results, and the cardiologist's nurse called me to bring me back into the office because she said that my echo showed that my heart was "enlarged" and there was some "dilation"...  
I am confused as to how my EKG could be "sooooo Normal" but my echo showed abnormal results?
I suppose I should wait to see the cardiologist in 2 days, but, it is soo mystifying to me that there could be soo much difference in interpretation and wether I should ask for a secind opinion if the doctor says there is something wrong with me.

[kenkeith]

The results of the EKG depend on electrical impulses and how the electrical impulses react to different conditions as it passes through tissue, etc..  Not a relaible source...better for heart rhythm  disorders.

The echo provides a visual output on a monitor that sees the heart with ultrasound waves and is able provide dimensions of heart walls and chambers.  The dimentions are estimates as the transducer (receives and sends ultra sound waves) cannot lock precisely on the moving heart walls.  The size may be in the margin of error that is about 10%.  I always ask for a copy of the report and dimensions, etc. that can be compared to a standard and also provides a reference for future tests.